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Biomedical subjects

A V Astrup

Publications and source records attributed to A V Astrup.

51 records · Page 3Linked to original sources
PubMed1995

[Objective assessment of the habitual dietary fat content in patients with obesity].

A diet rich in fat may be an important precipitating factor of obesity, but studies on this relation have been hampered by the lack of an objective method to assess habitual dietary fat content. We measured 24-h fat oxidation in a respiration chamber in 38 overwight or obese and 35 nonobese women, and used it as an estimate of habitual dietary fat energy (%). After adjustment for confounders, obese women had higher oxidative fat energy than nonobese women [40.2% (37.8-42.6) vs. 36.0% (33.6-38.5), p < 0.02]. Adjusted oxidative fat energy (%) increased with increasing size of fat mass, and this relation suggest that a 10-kg change in fat mass may be caused by a change in dietary fat energy of > or = 1.6%. This objective assessment supports the contention that obese subjects consume a diet with a higher fat content than nonobese individuals, and the high-fat diet may have causal importance for the development and maintenance of obesity.

Adult↗
PubMed1994

[The effect on health of dietary antioxidants and antioxidant supplements].

Reactive free oxygen radicals are formed in the reactions involved in normal cell metabolism. This formation is closely regulated e.g. by dietary antioxidants. Present knowledge suggests that an imbalance, with surplus of free radicals, can play a role in the pathogenesis of certain types of cancer, atherosclerosis, and cataract. A number of epidemiological studies have demonstrated a reduced risk of developing these diseases in persons who consume a diet with a high content of vegetables and fruit, which contains large quantities of the antioxidants: beta-carotene, vitamins C and E. Intervention studies, using supplements of these antioxidants, have so far not been able to show a beneficial effect. The apparently protective effect of fruit and vegetables may be due to other active ingredients. In Denmark the average intake of vegetables and fruit is low, and it is estimated that an increased consumption of these foods could reduce the occurrence of certain cancer types and atherosclerosis. In contrast, there is no evidence that antioxidant supplements would provide protection against disease, and their safety remains to be established.

Antioxidants↗
PubMed1994

[The importance of nutrition for the prevention of osteoporosis].

The prevalence of osteoporosis is increasing, and is a significant burden on society. Dietary composition is an important determinant of the bone mineral density in the growth period, and of the magnitude of the age related bone mineral loss, in particular among postmenopausal women. Therefore, an improvement of the diet has an important role in the prevention of osteoporosis. A sufficient intake of calcium and vitamin D can reduce the risk of fractures in postmenopausal women, and it is likely that a low calcium intake may affect peak bone mass negatively. Calcium in the Danish diet comes mainly from dairy products. Half a litre of milk and 25 g of cheese will cover most people's calcium requirement. Part of the calcium requirement may also be covered by consuming other foods such as cabbage, broccoli and beans. Children, adolescents and elderly individuals who avoid dairy products are recommended to take a calcium supplement. The status of vitamin D among the elderly can be improved by a daily outdoor stay and by a frequent intake of fatty fish such as herrings. Elderly persons who stay indoors are recommended to take a vitamin D supplement.

Adolescent↗
PubMed1993

[Effect of 3-month exercise training on daily energy expenditure in formerly obese women with reduced and stable weight].

Predisposition to obesity has been suggested to be related to a low energy expenditure (EE). This condition could be counteracted by physical exercise. In the present study we wanted to elucidate if aerob training could increase sedentary 24-hour energy expenditure in formerly obese subjects. Seven reduced-obese premenopausal women were studied in a respiration chamber before and after a three month period of aerobic training. No significant effects of training were seen on daytime, sleeping or total 24-hour EE. However, the change in daytime EE was positively correlated to the change in VO2max. Sleeping and 24-hour respiratory quotients were slightly increased after the training period. In order to reveal a possible role of the sympathetic nervous system in the observed effect of training, additional experiments were performed with beta blockade. However, no interactions between training and beta blockade were found.

Adrenergic beta-Antagonists↗
PubMed1993

Safety and efficacy of long-term treatment with ephedrine, caffeine and an ephedrine/caffeine mixture.

In a randomized, placebo-controlled, double blind study, 180 obese patients were treated by diet (4.2 MJ/day) and either an ephedrine/caffeine combination (20mg/200mg), ephedrine (20mg), caffeine (200mg) or placebo 3 times a day for 24 weeks. 141 patients completed this part of the study. All medication was stopped between week 24-26 in order to catch any withdrawal symptoms. From week 26 to 50, 99 patients completed treatment with the ephedrine/caffeine compound in an open trial design, resulting in a statistically significant (p = 0.02) weight loss of 1.1kg. In another randomized, double-blind, placebo-controlled 8 week study on obese subjects we found the mentioned compound showed lean body mass conserving properties. We conclude that the ephedrine/caffeine combination is effective in improving and maintaining weight loss, further it has lean body mass saving properties. The side effects are minor and transient and no withdrawal symptoms have been found.

Adult↗
PubMed1991

Reduced plasma noradrenaline concentrations in simple-obese and diabetic obese patients.

1. Obesity may be associated with a decreased activity of the sympathetic nervous system and also with a deficiency of the response to stimuli activating the sympathetic nervous system. As insulin activates the sympathetic nervous system, the present study was undertaken to measure the plasma noradrenaline concentration in the fasting state and after 75 g of oral glucose in simple-obese patients (n = 13), in non-insulin-dependent (type 2) diabetic patients (n = 37) and in normal control subjects (n = 12). 2. The fasting plasma noradrenaline concentration was similarly reduced in the simple-obese group and in the diabetic obese group compared with the control group (P = 0.005). The glucose-induced increase in plasma noradrenaline concentration was normal in the simple-obese group, but was abolished in the obese diabetic patients (P = 0.008). 3. Step-wise regression analysis indicated that independent effects on the fasting plasma noradrenaline concentration were exerted by age (r = +0.32, P = 0.002), glucose concentration (r = -0.32, P = 0.02) and the degree of obesity (r = -0.37, P = 0.007), but not by plasma insulin concentration. 4. These results show that obese patients have a reduced fasting plasma noradrenaline concentration independently of accompanying diabetes, but that the response of noradrenaline to oral glucose is only abolished in the obese diabetic patients.

Adult↗
PubMed1990

[Obesity and diabetes as side-effects of beta-blockers].

Overweight and obesity may develop in individuals with genetically determined low resting energy expenditure. Drugs are among the recognised precipitating factors. The obesity promoting impact of beta-blockers is, however, less well known. Resting energy expenditure, and thermogenesis induced by stimuli such as meals, cold and heat exposure, stress and anxiety, have a facultative component mediated by the sympathoadrenal system through catecholamines working on beta-adrenoceptors. Treatment with beta-blockers reduces the facultative thermogenesis by 50-100 kcal/d, which corresponds to the weight gain of 2-5 kg/year reported in clinical trials. Treatment with beta-blockers also results in insulin resistance, which may aggravate existing diabetes and elicit diabetes in predisposed patients. Overweight and obesity are frequently complicated with hypertension and angina pectoris, which are often treated with beta-blockers. Obesity is associated with a defective sympathetic activity, and treatment with beta-blockers may further reduce facultative thermogenesis and promote weight gain. The consequence may be aggravation of hypertension, insulin resistance and other atherogenic factors. The causal therapy of android overweight and obesity complicated with diabetes or hypertension is a sufficient weight loss. If pharmacological treatment is inevitable, combined treatment with diuretics and ACE-inhibitors are most appropriate.

Adrenergic beta-Antagonists↗
PubMed1990

Effects of nutrient intake on sympathoadrenal activity and thermogenic mechanisms.

Ingestion of carbohydrate results in a diphasic activation of the sympathoadrenal system. One component is an insulin-mediated activation of the sympathetic nervous system (SNS). This activation is partly a haemodynamic reflex, but it may cause a weak thermogenic effect via beta 1-adrenoceptors in white adipose tissue, the liver and the heart. The second thermogenic component of carbohydrate occurs later when the blood glucose concentration decreases towards baseline levels. This elicits an increased secretion of adrenaline from the adrenal medulla, and the circulating level exceeds the physiological threshold for thermogenic effect. The target is mainly skeletal muscle where thermogenesis is stimulated via beta 2-adrenoceptors. Also the basal metabolic rate and the thermogenic responses to cold and heat exposure, mental stress and exercise, have facultative components. Inhibition of facultative thermogenesis by beta-blockers such as propranolol, diminishes the daily energy expenditure and promotes weight gain and obesity. Although thermogenesis mediated by the sympathoadrenal system accounts for only a small part of the daily energy expenditure, it is sufficient to explain the positive energy balance and weight gain reported in patients receiving treatment with beta-adrenoceptor blocking agents.

Adrenal Glands↗